1. Field of the Invention
The present invention relates to communication networks and, more particularly, the present invention relates to techniques for charging coordination and other kinds of information coordination, and a common charging identifier for communication networks.
2. Description of the Related Art
In general, packet switched wireless networks provide communications for mobile terminals with no physical connection required for network access. The General Packet Radio Service (GPRS) in the Global System for Mobile Communications (GSM) and the Universal Mobile Terrestrial System (UMTS) have both been developed to provide wireless communications networks with a packet switched side, as well as a circuit switched side.
The specifications for UMTS networks with further improvements have been released by the 3rd Generation Partnership Program (www.3gpp.org). Release 00 of the UMTS specifications provides that a network subscriber can have one or more packet data protocol (PDP) addresses. Each PDP address is described by one or more PDP contexts in the Mobile Terminal (MT), the Service GPRS Support Node (SGSN), and the Gateway GPRS Support Node (GGSN). The GGSN is a gateway to external networks. Each PDP context may have routing and mapping information for directing the transfer of data to and from its associated PDP address and a traffic flow template (TFT) for filtering the transferred data.
Each PDP context can be selectively and independently activated, modified, and deactivated. The activation state of a PDP context indicates whether data transfer is enabled for a corresponding PDP address and TFT. If all PDP contexts associated with the same PDP address are inactive or deactivated, all data transfer for that PDP address is disabled. All PDP contexts of a subscriber are associated with the same Mobility Management (MM) context for the International Mobile Subscriber Identity (IMSI) of that subscriber. Setting up a PDP context means setting up a communication channel.
FIG. 1 is a process flow diagram that illustrates an example of the PDP context activation procedure. In step 100, the MT sends an Activate PDP Context Request to the SGSN. The Activate PDP Context Request message sent in step 100 includes a number of parameters. The parameters include a PDP address and an Access Point Name (APN). The PDP address is used to indicate whether a static PDP or dynamic PDP address is required. The APN is a logical name referring to the Gateway GPRS Support Node (GGSN) to be used.
In step 102, the SGSN sends a Radio Access Bearer (RAB) setup message to the UMTS Terrestrial Radio Access Network (UTRAN) or the GERAN or other corresponding radio access networks. In step 104, the SGSN sends a Create PDP Context Request message to the affected GGSN. The GGSN decides whether to accept or reject the request. If it accepts the request, it modifies its PDP context table and returns a Create PDP Context Response message in step 106. The SGSN then sends an Activate PDP Context Accept message to the Mobile Terminal in step 108.
In Release 00 of the Universal Mobile Telecommunications System specifications (UMTS), a new architecture with existing and new logical entities is introduced to support IP multimedia services including, e.g., IP telephony. SIP (Session Initiation Protocol) is used for call control. The caller allocates a Call Id, which is included in SIP messages. The Call Id uniquely identifies the call and is used by all call participants However, the use of the Call ID is complicated in the case of a mobile station (MS) comprised of mobile terminal (MT) and terminal equipment (TE) parts since the MT driver in the TE is preferably able to filter the UDP/IP packets forwarded to the MT, and be able to parse the majority if not the entire SIP grammar to find the Call-ID field contained somewhere in a UDP datagram.
The subscribers of voice services are accustomed to receiving bills based on calls, not based on the transport resources used for making the calls. Subscribers of IP telephony often expect similar billing criteria. Consequently, billing for the services used (e.g., for the calls) rather than the transport resources used is becoming increasingly important. In the case of Wireless Application Protocol (WAP) services, billing for services rather than transport resources is already the expectation.
For an IP telephony call, a PDP context is required to carry the actual voice traffic. Both the GPRS/UMTS layer and the IP telephony layer collect charging information (CDRs): the GPRS/UMTS layer collects charging information for the PDP context while the IP telephony layer collects charging information for the call. A common identifier ought to be added to the CDRs to make it possible to bill based only on the CDRs created by the IP telephony layer (i.e., for services) and to omit the CDRs created by the GPRS/UMTS layer (i.e., for transport resources).
A common identifier is needed in the CDRs created by the GPRS/UMTS layer and by the IP telephony layer to make it possible to omit certain CDRs and enable billing based on services rather than use of transport resources. More specifically, in many cases it would be advantageous to selectively omit CDRs created by the GPRS/UMTS layer or CDRs created by the IP telephony layer. If that were possible, the billing would be operator-specific, in that the operator could decide how to bill the subscribers (how to use the created CDRs).
In spite of the numerous details provided in the aforementioned protocol, many features associated with mobile networks have not been dealt with. Specifically, charging information can be created by the SGSN, the GGSN and by the IP telephony network elements, e.g. the CSCF. At present there is no solution in place to associate the charging information created by the SGSN, the GGSN and the charging information created by the CSCF. Indeed, the network may be so complicated (e.g., the charging data may be generated in many different network elements) that it is not possible to combine all call event related data. At least some of this data is needed in order to implement network functionality such as hot billing or merely to allow a network operator to implement joint billing for GPRS services and IP telephony services.